Answer:B
Explanation:
Initial velocity, u=0m/s
Distance,s=20m
a=+g=9.8m/s*s
Using v*v=u*u+2gs
v*v=0+2*9.8*20
v*v=392
v=19.8
When s=20m, v = 19.8m/s
Therefore when v = 10m/s, s= 10*20/19.8
s =10.1m
1. No they aren’t because they all belong to different sports and are used differently
<span>The particles through which compressional waves travel move in the same direction as the wave. This may be observed by fixing one end of a large spring and then compressing and extending the other end. The wave travels from one end to the other and the spring's parts move in the same direction.</span>
Answer:
1 second
Explanation:
h = −16t² + 32t
When, h = 16
16 = −16t² + 32t
Divide each of the numbers by 16
1 = -1t² + 2t
Rearrange the equation
1t²-2t+1 = 0
Solving by the quadratic formula, we get
![t=\frac{-(-2)\pm \sqrt{(-2)^2-4\times 1\times 1}}{2\times 1}\\\Rightarrow t=\frac{2\pm 0}{2}\\\Rightarrow t=1\ s](https://tex.z-dn.net/?f=t%3D%5Cfrac%7B-%28-2%29%5Cpm%20%5Csqrt%7B%28-2%29%5E2-4%5Ctimes%201%5Ctimes%201%7D%7D%7B2%5Ctimes%201%7D%5C%5C%5CRightarrow%20t%3D%5Cfrac%7B2%5Cpm%200%7D%7B2%7D%5C%5C%5CRightarrow%20t%3D1%5C%20s)
So, time taken by the dolphin to jump out of the water and touch the trainer's hand is 1 second.
Acceleration = (final velocity-initial velocity)/time taken
=(30-10)/5
= 4m/s2
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